Process for cleaning fabrics

ABSTRACT

A PROCESS FOR CLEANING SOILED FABRICS WHICH UTILIZES AN APPARENTLY DRY CLEANING MEDIUM COMPRISING A FINELY PARTICULATE CARRIER ADSORBED WITH A CLEANING LIQUID. THE SOILED FABRIC IS PLACED INTO A PLENUM CONTAINING THE CLEANING MEDIUM AND THE MEDIUM IS FLUIDIZED BY DIRECTING AN AIR STREAM THROUGH THE PLENUM. DIFFERENTIAL MOTION IS APPLIED BY TRANSDUCER MEANS TO THE PARTICULATES OF THE MEDIUM WHILE THE FABRIC IS IN THE PLENUM. THE FOREIGN MATERIAL CARRIED BY THE FABRIC IS TRANSFERRED TO THE CLEANING MEDIUM DUE TO THE SOURING ACTION OF THE MEDIUM. THE APPARATUS FOR THE PROCESS COMPRISES AN ENCLOSURE HAVING WITHIN IT THE MENTIONED PLENUM, MEANS FOR RETAINING THE SOILED FABRIC WITHIN THE PLENUM AND MEANS FOR DIRECTING AN AIR STREAM THROUGH THE CLEANING MEDIUM TO FLUIDIZE THE CLEANING MEDIUM AND THEREAFTER T RECIRCULATE THE AIR STREAM. TRANSDUCER MEANS APPLIES A DIFFERENTIAL MOTION TO THE PARTICULATES TO AID IN THE CLEANING ACTION.

May 4, 1971 A. E. LEVAN ETAL 3,577,214

PROCESS FOR CLEANING names Filed Oct 19, 19s? 2 Sheets-Sheet 1 UnitedStates Patent 3,577,214 PROCESS FOR CLEANING FABRICS Ambrose E. Le Van,Short Hills, N.J., and David Tatum, Swarthmore, Pa., assignors toAmetek, Inc., New York,

Filed Oct. 19, 1967, Ser. No. 676,503 Int. Cl. B08!) 7/04 US. Cl. 8-1379 Claims ABSTRACT OF THE DISCLOSURE A process for cleaning soiledfabrics which utilizes an apparently dry cleaning medium comprising afinely particulate carrier adsorbed with a cleaning liquid. The soiledfabric is placed into a plenum containing the cleaning medium and themedium is fluidized by directing an air stream through the plenum.Dilferential motion is applied by transducer means to the particulatesof the medium while the fabric is in the plenum. The foreign materialcarried by the fabric is transferred to the cleaning medium due to thescouring action of the medium. The apparatus for the process comprisesan enclosure having within it the mentioned plenum, means for retainingthe soiled fabric within the plenum and means for directing an airstream through the cleaning medium to fluidize the cleaning medium andthereafter to recirculate the air stream. Transducer means applies adifferential motion to the particulates to aid in the cleaning action.

The present invention relates to a process for cleaning fabrics and,more particularly, fabrics in finished and sewn form which are heavilysoiled, for example continuous roll towels utilized in lavatories,uniforms worn by service personnel and the like. The present inventionrelates as Well to apparatus for carrying out such fabriccleaningprocess. The term fabric as used herein shall mean fabric in all forms,including unfinished and finished lengths of fabric and fabric inmanufactured articles such as wearing apparel.

As is well known, fabrics become soiled when subjected to use andexposed to particulate materials or fluids that sorb onto the surfacesof the fibers of the fabric or become entrapped within the intersticesof these fibers, within fabric infra-structures and within the folded orsewn portions of various fabric articles, such as wearing apparel.

Many different processes to clean fabrics have been devised and used.Common laundering with hot and cold water, cleaning with steam jets,cleaning with non-aqueous liquid solvents and by condensing vapors ofsuch solvents and fulling by tumbling materials in barrels charged withfullers earth, sawdust and like absorbing materials all have found theirhistorical uses and benefits. Many of the liquid processes utilized toclean and to scour fabrics require the use of additives in the cleaningmedium for various specific purposes such as to promote detergency,prevent redeposition of soil, act as builders, promote foaming, causeemulsification, suspend soil, and to act as bleachants, opticalbrighteners, bactericides, emollients, stabilizers, wetting agents andthe like.

One disadvantage common to these cleaning methods which utilizeadditives is the continual drainage of these additives into the wastestream as eflluents from the cleaning operation. These losses must becontinuously replaced to keep the cleaning operation functioningproperly.

One of the disadvantages in the cleaning of fabrics is particularlyfound in the cleaning of continuous roll towels of the type located inlavatories. It is now required that these roll towels be placed intodispensing units at various and dispersed lavatory locations where theyare convenient to users. After these roll towels become soiled ICCthrough use, the rolls must be collected and delivered to a centralizedlaundry to be washed, sterilized, dried and ironed, using normal wetwash cleaning means and mangles to finish the rolls. Then the towelrolls must be redistributed to the various lavatory locations.

Similarly, the uniforms worn by various service personnel often becomeheavily soiled. Typical of these are doctors and nurses white coats anddresses, and whites worn by various hospital personnel. These uniformsmust be distributed to various locations in a hospital where they areconvenient for these personnel to pick up and don. After these uniformsbecome soiled, they must be taken from these various locations andbrought to a central laundry for wet washing, drying and pressing.Thereafter, the uniforms are redistributed to the various hospitallocations.

It is the primary object of this invention to provide a cleaning processand apparatus therefor which replaces the traditional steps of washing asoiled fabric with a liquid medium, then drying the fabric and ironingthe fabric with a process utilizing an apparently dry cleaning medium.

It is another object of the present invention to provide a process forcleaning fabrics which utilizes a fluidized cleaning medium including aparticulate carrier impregnated with a cleaning agent which is broughtinto contact with the soiled fabric and removes the foreign matter fromthe fabric so that the fabric becomes clean without the conventionalrequirement for liquid Washing, drying and pressing.

It is another object of the present invention to provide a process forcleaning fabrics and apparatus therefor especially well suited to cleanand sterilize roll towels while these roll towels are within theirrespective dispensing units in lavatories so that the costly requirementof collecting these roll towels from the lavatories, sending these rolltowels for cleaning to a centralized laundry and the subsequentredistribution of the roll towels to dispensing units in lavatories iscompletely eliminated.

It is still another object of the present invention to provide anapparatus for carrying out the above described process for the cleaningof fabrics, the apparatus being suitable for location in homes,institutions and the like and being adapted to have placed thereinsoiled fabrics which are to be cleaned and which carries out thecleaning process without the use of a liquid cleaning medium and withoutthe use of fullers tumbling barrels.

It is another object of the present invention to provide a process andapparatus of the character described for cleaning fabrics in acontinuous cleaning operation in a central industrial depot where soiledroll towels and other soiled fabrics items can be cleaned andconditioned with out the need of drying or pressing.

In general, the present invention utilizes a fluidized bed or carriercomprised of very finely divided solid particulates which are apparentlydry and free flowing. Such a carrier made up of particulates can bemaintained in a so-called fluidized or expanded state even though asurprisingly large quantity of liquid, even up to 50% by weight of thesolid particulate mass, is adsorbed onto the surfaces of the finelydivided solid particulates. The liquid can be comprised of constituentssuch as an aqueous emulsion of odorless kerosene or cleaners naphtha,the two liquid phases of which contain suitable additives to promotedetergency and the cleaning of fabrics. The liquids and emulsionsadsorbed onto the surface of the solid particulates act as though theywere in the form of a usual extensive wash bath of bulk liquid oremulsion.

In applying the fluidized carrier to the soiled fabric, a transversepressure gradient or vigorous differential fluidmechanical force such asthat which causes a streaming 3 potential in fluids is required topromote desorption forces to act on the soil carried by the fabric andto transfer the soil from the fabric to the fluidized carrier. The mereimmersion of soiled fabric in the described dampened fluidized carriercontaining surface-adsorbed detergent liquid on the free flowing solidparticulates is insufficient to remove or transfer soil readily from thefibers of the soiled fabric to the fluidized particulate surfaces. Themagnitude of the necessary fluid-mechanical forces in action at theinterface between the fabric, the soil carried by the fabric and thefluidized carrier can be reduced when certain wetting agents anddetergency promoting additives are utilized in the liquid which dampensthe solid particulates.

The apparatus for carrying out the above process comprises an enclosureand a mechanism adapted to support fabric articles within the enclosure.The enclosure defines at least three plenums in a vertical array. Thefirst and lower plenum is provided to diffuse a vertically-rising airstream and to direct the stream to rise through a finely perforatebarrier into the second and intermediate plenum in which the cleaningmedium is fluidized by the aerodynamic lift forces of the diffused airstream. A third uppermost plenum collects the exhaust air from thesecond plenum for recirculation. Soiled fabric can be lowered into andbe returned from the intermediate plenum.

Force transducer means is provided within the fluidized carrier plenumto establish the required fluid-mechanical differential motion of theparticulates of the carrier so as to scrub the surface of the fabricwhile it is situated within the intermediate plenum. The transducercauses the actively detergent dampened solid particulates to impingeupon, adhere to and be detached from the surfaces of the fibers of thefabric within the fluidized carrier stream. The differential motionrequired can also be obtained by high-impulse vibration of the fabricarticles.

The above brief description, as well as further objects, features, andadvantages of the present invention, will be more fully appreciated byreference to the following detailed description of presently preferred,but nonetheless illustrative embodiments in accordance with the presentinvention, when taken in conjunction with the accompanying drawings,wherein:

FIG. 1 is a transverse cross sectional view of an apparatus for bothdispensing a roll towel and cleaning the soiled towel at a lavatory;

FIG. 2 is a partially broken away view of an apparatus for cleaningsoiled roll towels at a central station; and

FIG. 3 is a cross sectional view taken substantially along the line 33of FIG. 2.

The process carried out by the apparatus of the figures utilizes afluidized carrier comprised of finely divided solid particulates and adampening liquid adsorbed onto the surfaces of the particulates. Thefinely divided solid particulates of the carrier may comprise bentonite,attapulgite clay, expanded perlite, montmorillonite, kaolinite, fullersearth, diatomaceous earth, colloidal magnesium silicate, or chalk orcombinations thereof. The dampening liquids include water, cleanersnaphtha or odorless kerosene. In each case, the quantity of dampeningliquid adsorbed by the carrier is such that the carrier with itsadsorbed liquid remains apparently dry. This may be up to 50% by weightof the solid particulate mass.

In addition to the above, one or more additives may be incorporated intothe cleaning medium for various purposes. The additives may includeemollients such as glycerine, glycol alcohols, and wool grease orlanolin; fireproofing agents such as chlorinated hydrocarbons, borax,and tris (2,3-dibromopropyl phosphate); antiredeposition or soilsuspending agents such as sodium carboxymethyl cellulose, starchderivatives, methyl cellulose, C saturated fatty acid soap, polyvinylalcohol, polyvinyl pyrrolidone, water soluble proteins such as gelatine,and gluconic acid; solubilizing agents such as glycol ethers, urea,

dicyandiamide, xylenesulfonate, and dodecylbenzenesulfonate; cleansingpower synergists such as aliphatic solvents, aromatic hydrocarbons,chlorinated solvents, oxygenated solvents, condensed phosphates assodium tripolyphosphate and sodium pyrophophate, and condensed silicatesas sodium metasilicate; antidusting components such as glycol ethers,carbowax, polyvinyl methyl ether, and polyvinyl isobutyl ether;anticaking components such as sodium sulfate; wetting agents such asfatty alkyl sulfate and polyoxyethylene nonionics; optical brighteningand bleaching agents which are water soluble as triazinylstilbene orwhich are alcohol soluble as coumarin, benzoxazole and benzimidazole;bleachants such as perborate, persulfate and percarbonate; foamsuppressants such as polymeric nonionics (pluronic series) and taurides;bactericides such as quaternary ammonium cationics,methylene-bis-chlorophenols and thio-bis-chlorophenols; a water solublesolvent such as isopropanol; emulsifiers such as mahogany sulfonates,amine soaps, naphthenates, alkylarylenesulfonates, alkanesulfonates, andpolyoxyethylene fatty ester; emulsion stabilize-rs such aspolyoxyethylated fatty alcohol and lecithin phosphatides; couplingagents such as n-butyl alcohol and glycol ethers; and water evaporationpreventives such as oleic acid.

The following is the formulation of an embodiment of the cleaningmedium:

PART I Ingredient: Parts by weight Water Ethylene oxide condensate 1.5Oleic acid .05 Alkyl benzene sodium sulfonate .3 Sodium sulfate .5Sodium metasilicate 1.0 Glycerine .5 n-Butyl alcohol .1 Borax 1.0 Sodiumperborate .5 Sodium carboxymethyl cellulose .5 Dodecylbenzenesulfonate.05 Sodium tripolyphosphate .5 Lecithin phosphatide .3 Triazinylstilbene2.5

PART II Odorless kerosene 100 Chlorinated hydrocarbon 15Tris(2,3-dibromopropyl phosphate) 1.0 Polyoxyethylene fatty ester 1.5Coumarin 1.0 Methylene-bis-chlorophenol .1 Isopropanol 5.0 Polyvinylmethyl ether .05 Lemon oil .05

Part I is prepared by dissolving all ingredients in the Water, cold,with vigorous stirring. Part II is prepared by adding kerosene,chlorinated hydrocarbon and tris(2,3- dibromopropyl phosphate) together.The remaining in- 'gredients are added to and dissolved in theisopropanol which is then added slowly with vigorous stirring to thewarmed kerosene portion. Part II is added slowly while hot to Part Iwhich is vigorously stirred while cold to emulsify and disperse. Thedispersion is added to a suflicient quantity of dry finely dividedbentonite clay to wet the clay portion to a uniform dry crumb. To thisdry crumb additional bentonite clay or white chalk is added and stirredand tumbled to produce a free flowing elutriable powder medium.

Referring now in detail to the drawings, FIG. 1 shows an apparatus 10which is adapted to be stationed in a lavatory and which both presents acontinuous length of roll towel for use and cleans the roll towel sothat a length of fresh towel is always available to a user. Thedispensing and cleaning apparatus 10 has an appropriately shapedenclosure 12. A continuous endless loop length of a towel roll 14 ishoused by the enclosure and portions of the roll are situated bothinterior of the enclosure as at 14a and exterior of the enclosure as at14b. The roll towel is guided along a path of travel by a number ofguide rollers 16. To prevent the rollers from compacting the cleaningmedium into the fabric, the rollers may be porous. The foregoingarrangement including the enclosure, roll towel and towel transport iswell known.

The enclosure 12 includes an internal chamber 18 which is divided intothree plenums, which are in vertically stacked series array. The firstand lower plenum 20 serves as an air stream diffusion plenum. The secondand intermediate plenum 22 is separated from the first plenum 20 by afinely perforate horizontal barrier wall 24.

A quantity 26 of the of the previously described cleaning medium iscontained within the second plenum 22 and accordingly this plenumconstitutes the cleaning plenum. This quantity of the medium comprises abed which is retained in a fluidized state by the aerodynamic lift ofthe air stream passing upwardly from the lower plenum through thecleaning plenum. The roll towel 14 in its path of travel passes throughthe cleaning plenum 22 and said path includes a horizontal leg whichlies near the perforate wall 24 and across the air stream rising fromthe air diffusion plenum. A third and upper plenum 30 serves to collectexhaust air which has risen from the cleaning plenum 22. The thirdplenum has a filter 31 which prevents loss of the cleaning medium, and ahood 32. An air recirculation system 34 leads air from the hood 32 via afluid duct 36 to an air pump 38. The pump exhausts air through anotherfluid duct 40 back into the lower plenum 20.

The shown horizontal leg of the towels path of travel may cause toogreat a pressure drop, if the fabric is tightly woven. In such case, itis desirable to guide the fabric along a more vertical path.Alternatively, if it is desired to employ the aforesaid horizontal leg,supplementary fluidizing means may be employed above the horizontal leg.

Force transducer means is provided to impart differential motion to thecleaning medium particulates while the fabric is in the cleaning plenum.Said means may typically comprise a mechanical vibrator 28 held by awall of the enclosure 18. The vibrator has a head 28a in contact with aportion of the towel roll 14 within the cleaning plenum. There may beone or more of such vibrators located at different points along the pathof travel of the towel roll. The foregoing mechanically agitates thefabric and imparts high impulse jerk stresses to the fabric whichassists in loosening and detaching the soil mechanically from thefabric. The head may be reciprocated by a motor-driven eccentric in aknown manner.

In addition to the mechanical vibrator 28 or in lieu thereof, the forcetransducer means may comprise well known vibration apparatus 29 such asa jet edge sonic generator or a Hartmann sonic generator. Mechanicalscrubbing action may also be achieved by adding a limited number ofinert, larger size particles to the 'bed.

Desirably, a heater 42 is provided to establish a slightly elevatedambient temperature in the cleaning medium within the cleaning plenum22. A vacuum cleaning unit 43 may be provided along the path of travelof the roll at a location past the cleaning zone to remove residualparticlulate material from the towel. Should the towel be slightly dampfrom use, this factor will enhance the cleaning action.

The operation of the apparatus 10 will be apparent in view of theprevious disclosure. Briefly, the towel roll 14 has an exposed hangingportion 14b which is utilized to clean and dry the hands of a personutilizing lavatory facilities. In its path of travel, the towel rollpasses through the cleaning medium 26 contained in the cleaning plenum22. While a soiled portion of the towel roll is being transportedthrough and is temporarily located within said cleaning plenum, thetransducer means 28 is activated to mechanically beat the soiled fabricto promote cleaning action. The vibrator 29 is also energized to agitatethe particulates of the cleaning medium. It will be understood that, asis conventional, each user will pull a fresh length of towel from theapparatus thereby bringing a soiled section into the cleaning plenum.

The fluid circulation system 34 is put into operation when a length offabric is to be cleaned so that an air draft passes from the lowerplenum 20 upwardly through the finely perforate wall 24 through thecleaning plenum 22 (and against, through and around any fabric therein)and upwardly to the upper plenum 30 and back through the duct 36, theair pump 38 and the fluid duct 40 for recirculation purposes. The resultis the removal of soil from the towel roll without any requirement forthe wetting or pressing of the towel roll itself. It will be apparentthat the foregoing transducer means and air circulation system can becontrolled so as to be activated for only a certain desired period oftime after a soiled length of towel arrives in the cleaning plenum. Aresident time in the range of five minutes is believed to be sufficientfor proper cleaning action.

Another embodiment 42 of an apparatus in accordance with the presentinvention is shown in FIGS. 2 and 3. The apparatus of this embodiment isadapted to clean soiled roll towels on a continuing basis at a centrallaundry station. The apparatus 42 has an enclosure 44 and a length ofsoiled towel 46 is situated therein. The towel 46 runs from a towel feedroll 48 to a towel take-up roll 50.

The enclosure 44 is divided into a lower air diffusion plenum 52 and anintermediate cleaning plenum 54. These two plenums are separated by afinely perforate barrier 56. An upper air collection plenum 58 issituated above the cleaning plenum 54 and utilizes a filter 60. An aircirculation system, generally '62, exhausts air from the upper plenum 58and directs the air back into the air difliusion plenum 52. Theenclosure 44 has a removable cover 64 to permit access into the interiorof the cleaning plenum 54. The towel transport system, including therolls 48, 50 may be motor driven as at 66.

In operation, a rolled length of soiled towel is loaded on the feed roll48, is guided by guide rolls 16' through the cleaning plenum 54 and isthen wound on the take-up roll 50. The air circulation system 62 forcesair from the air diffusion plenum 52 through the perforate barrier 56and into the cleaning plenum 54. This flow of air fluidizes the cleaningmedium 26' in this plenum and this action, together with the action ofthe transducer means 28' as described in connection with thefirst-mentioned embodiment, serves to remove soil from the fabric as itpasses through the cleaning plenum. Each segment of the towel 1sresident in the cleaning plenum for a period of time proper for thecleaning action to be completed. The air is recirculated through thethird plenum 58.

In an alternate embodiment, soiled fabric garments such as hospitaluniforms are hung within the cleaning planum 54 of the second embodiment42 and are exposed to the action of the cleaning medium 26' for apredetermined period of time. Thereafter, the garments are removed incleaned condition and without the necessity of pressing, or drying as isnecessary with conventional cleaning operations. In a hospitalsituation, the garments would be hung in the apparatus at the end of aworking day, and would then be ready for use the next morning. Theuniforms would be supported by conventional garment hangers supported bya rack within the cleaning plenum.

It is to be understood that the above-described arrangements areillustrative of the application of the principles of the invention.Numerous other arrangements may be devised by those skilled in the artwithout departing from the spirit and scope of the invention.

What we claim is:

1. A process for cleaning soiled fabrics comprising the steps of (a)supporting a soiled fabric in a cleaning plenum in which is situated aquantity of a dry-to-the-touch particulate cleaning medium (b)circulating a gaseous stream upwardly through the cleaning plenum tofluidize the cleaning medium so as to form a cleaning be'd whereby theparticles of the cleaning medium scour the soiled fabric within thecleaning plenum, and simultaneously preventing said particles frompassing with the stream out of the plenum; and

() imparting additional differential motion to the soiled fabric withrespect to the particles of the medium to aid in the removal of soilfrom the fabric.

2. A process for cleaning soiled fabrics as set forth in claim 1 furtherincluding the step of continuously recirculating the gaseous streamthrough the cleaning plenum.

3. A process for cleaning soiled fabrics as set forth in claim 1 whereinthe step of imparting differential motion is carried out by mechanicallyvibrating the soiled fabric while it is in the cleaning plenum.

4. A process for cleaning soiled fabrics as set forth in claim 1 whereinthe step of imparting differential motion is carried out by sonicvibration.

5. A process for cleaning soiled fabrics as set forth in claim 1 furtherincluding the step of training the fabric through a predetermined paththrough the cleaning plenum, said path lying in a plane generallyperpendicular to the gaseous stream passing through the cleaning medium,while the gaseous stream is passing through the cleaning plenum.

9. A process for cleaning soiled fabrics as set forth in claim 1 whereinthe soiled fabric comprises an endless loop rolled towel, the processfurther including the step of guiding a portion of the towel along apredetermined path in the cleaning plenum, said path lying in a planegenerally perpendicular to the gaseous stream passing through thecleaning plenum, and simultaneously exposing another portion of thetowel outside of the plenum for use.

References Cited UNITED STATES PATENTS 3,432,253 3/1969 Dixon 8142 MAYERWEINBLATI, Primary Examiner US. Cl. X.R.

